@mtholder, @snacktavish : FYI - I'm passing three additional ID types here, in case you ever need to add annotation elements (events, agents, messages) in NCLconverter.

It looks like we're using the same type-specific id prefixes (```edge123```, ```trees5```, etc.) in NCLconverter and the curation webapp. But it makes me nervous that if a prefix changes on either end, we'll probably end up with duplicate ids after all. How would you feel about me sending ```firstAvailableEdgeID=edge124``` instead of just ```124```. Or alternately, sending another set of type-specific prefixes like ```edgePrefix=edge```, ...?